Optical communication systems, in general, include means for generating a modulated beam of light, means for transmitting the beam of light over a long distance, means for receiving the beam of light and means for converting the received beam of light to an electrical signal. When the beam of light is to be transmitted over a long distance, it is often necessary to periodically amplify the beam. In communication systems that use optical fibers for transmitting the beam, it is only necessary to periodically couple the optical fiber into an amplifier. However, for communication systems in which the beam is transmitted through free space, the amplifier must not only be capable of amplifying the beam of light, but must also have the capabilities of receiving the beam of light from free space and of retransmitting the amplified beam into free space.